Transmit Diversity with More than Two Transmit Antennas

Recently, a new form of transmit diversity has been developed and included for Interim Standard 2000 (IS-2000), the third generation successor for IS-95 code division multiple access (CDMA) systems. This transmit diversity scheme was developed by Bell Laboratories and uses Space-Time coding techniques. This paper presents performance results of this new transmit diversity method, termed space-time spreading, and investigates "open-loop" improvements to the scheme which use more than two antennas. Additionally, we investigate the performance improvements possible with closed loop techniques.